[CRITICAL] Add version to outgoing messages

@Renelvon @dionyziz Don't know how you want to handle PRs for patches like this into the latest version. This is a placeholder until I hear from you, but this is the requested update. Very simple.

- Added constant for version of release in constants.py
- Added 'v' value representing node's version number in send messages

This version number will help us see what version nodes are running on when diagnosing issues in the future.